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randyf

Well-known member
Joined
Nov 8, 2010
Posts
61
I have a couple of digital clocks and every few weeks or less I will see both of them gaining a minute about every 15 seconds.  This may go on for a few hours or less and then stop and not see it again for a few weeks or more.  All my outlets are off the inverter and was wondering if this could be the problem.  I used a Fluke and checked the voltage and frequency while this was happening and all was good.  120 volts at 60 Hz.  It is not a full sine wave inverter but strange that it only happens every few weeks, more or less.
 
Unless I'm mistaken digital clocks do not rely upon the frequency of the AC power.  They generally have a crystal or some other method of counting.  60 HZ AC frequency is used primarily in electric clock.
 
George, not true.  We've had several digital clocks, primarily in coffee makers, that would run fast on the MSW inverter power.  Our current coffee maker runs about a minute fast every 15 minutes or so on inverter while our previous ones ran at double time.  And others have no problem with the power, like our microwave oven clock.
 
Digital clocks are notorious for going off time on inverters. Usually the problem is with MSW because of the square wave, but any unusual shape in the wave can throw them off, depending on how their sampling algorithm works.

I've solved that problem in the coach by getting the kind of clock that has its own time source, the automatic-self-set type or the "atomic clock" type. The self-set does use an internal crystal and the atomic clock auto-corrects from radio signals.
 
That's what we need, a coffee maker with an atomic clock :)
 
I think you are right, Ned.  Doesn't the atomic pile provide free power ?. Runs the heating element as well...

    8) ::) ;D
 
I'm waiting for the cold fusion models to appear.
 
BigLarry said:
It sounds like you might need to also pick up a surplus lead suit, Ned ;D

If only they had my size.
 
Ned said:
I'm waiting for the cold fusion models to appear.

Cold fusion coffee.  Sounds like you may have just given Starbucks another name to give a beverage to make a few million dollars more on. 

Got your name in the hat for those checks that make you rich?
 
I claim a copyright on the phrase "cold fusion coffee" :)
 
There was an article in the news a few months to a year back about the feds relaxing standards on power companies concerning the maintaining of frequency.  This relaxation in standards was to help the power companies save money by not needing so much stand by power to maintain the frequency.  It was noted that this could cause some clocks to run slow or faster.  I forget the specifics of the article but changing the spec from .1 hz to .5 rings a bell. 

Shifting frequency reminds me of some of my old submarine stories....
 
I had shrimp and grits for breakfast this morning (Marathon) I just had an atomic pile. 

Actually I have learned a lot from you guys since I have been reading your blogs.  How come the invertor does not screw up appliances when you run them on a invertor if it speeds up the clocks?

Don't get too technical my brain is in retirement mode..

Jim

Spell checker still OTS?
 
Jim, many power supplies, such as computers and cell phone chargers, are switching supplies and aren't affected by the frequency differences.  Resistive appliances, like electro-mechanical toasters, aren't either.
 
Ned

If brains were dynamite I could not blow my nose, freq in power supplies? Like 110/220?  What you were talking about was the first I was aware of such a thing.  Every time I read this blog I learn something new. I will say some of the conversations are above my pay grade.

Jim
 
Actually, the frequency of the inverter output is quite close to 60Hz, but the waveform from a MSW inverter is actually square.  That's what causes the clocks to run fast (or slow).  But switching power supplies don't care about the waveform any more than they care about the frequency.  Some don't even care about the voltage, they'll be marked 120/240V 50/60Hz and are made to work both here and in the rest of the world.
 
Circuit boards that do pulse-width-modulation also have trouble with MSW inverter power, but I couldn't begin to explain exactly why. Suffice it to say that if you are working directly with the wave form rather than just average voltage, you better understand what the wave looks like. If you assumed it is always a sine wave and somebody slips in a square wave with a different amplitude, odds are your circuit design will do unintended things.
 
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